"Given that we know pilots and flight attendants admit that they sometimes accidentally leave their phones on, it’s likely not a huge safety risk," says Warren Chang, vice president and general manager of Fly.com, a travel website owned and operated by Travelzoo. "But the rules are the rules and people should adhere to the rules until the FAA has completed their safety study."

“Right now, a government-industry group is examining ways to help the FAA decide if it can allow more widespread use of electronic devices. We expect their report at the end of July. The FAA will review the report and determine next steps,” e-mailed Kristie Greco, an FAA spokesperson.

Greco pointed out that the FCC has banned use of cell phones in flight since 1991.

Rob Hodges, a spokesperson for http://www.mobiles.co.uk/, the UK’s first retail mobile phone site, described some potential risks via e-mail: “Similar to how noise can be created on a baby monitor through a mobile phone, a passenger using their device in such close proximity to the planes equipment, could generate noise and cause a distraction to the pilot.”

There is also potential for interference due to varying phone frequencies and the variety of radios onboard for communication with ground control, positioning and weather detection.

“Takeoff and landings are key moments when the pilot can’t afford to miss instructions. It makes sense to switch off phones during these phases,” wrote Hodges.

Even carriers such as Emirates and Virgin Atlantic that allow some calls in flight require mobiles be turned off for takeoff and landing.